fix(desktop): DeerFlow UI — ChatArea refactor + ai-elements + dead CSS cleanup

ChatArea retry button uses setInput instead of direct sendToGateway,
fix bootstrap spinner stuck for non-logged-in users,
remove dead CSS (aurora-title/sidebar-open/quick-action-chips),
add ai components (ReasoningBlock/StreamingText/ChatMode/ModelSelector/TaskProgress),
add ClassroomPlayer + ResizableChatLayout + artifact panel

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

desktop/src/lib/kernel-skills.ts

@@ -109,7 +109,11 @@ export function installSkillMethods(ClientClass: { prototype: KernelClient }): v
   }> {
     return invoke('skill_execute', {
       id,
-      context: {},
+      context: {
+        agentId: '',
+        sessionId: '',
+        workingDir: '',
+      },
       input: input || {},
     });
   };